Coagulant for purifying water and process of purifying water therewith



- Patented Apr. 28, 1925.-

LEVIS MILLERBOOTH, F PLAINFIELD, JERSEY.

PATENT OFFICE.

COAGULANT FOR PURIFYING- WATER AND PROCESS OF PURIFYING WATER THEREWITHNo Drawing.

To all whom it may concern:

Be it known that I, LEYIS MILLEa Booriu', a citizen of the UnitedStates, residing at 975 Cedar Brook Road, Plaintield, county of.

sulphates, usually aluminum sulphate or iron sulphate, whose chemicalactivity and consequent etiiciency was dependent upon the alkalinity ofthe water to be treated as manifested by the presence of alkaline salts,usually alkaline salts of calcium, magnesium or sodium. The percentageof salts in 2 waters-to be treated vary greatly from time to time. \VhenWater to be treated was markedly lacking in alkalinity it was customaryto supply a solution of sodium carbonate or other suitable alkali whichwas fed or introduced into the water separately.

When the process was continuous this involved apparatus for feeding themetallic sulphate and separate apparatus for feeding the alkalinesubstance. \Vhen the process 3 was intermittent it involved accuratelymeasuring and feeding the correct quantity of each'of the reagents. Whenthe metallic sulphate-urns supplied in such quantity that it did notcompletely react with the alkaline 40 substance supplied or contained inthe water to be treated, either because the water did not contain asutiicient quantity of alkali or because a sutlicient quantity of alkaliwas not supplied, the treated water was corro- 43 sive in its action anddamage to the appa- V ratus and to the product in connection with whichthe water was used resulted, due to the acidity of the undecomposedmetallic sulphate remaining in the water, and water so treated wasunsuitable for washing and for numerous other requirements.

Hy invention is an improvement and simplitication of the above processand is designcd to eliminate the ditlicultics men- I Application filedOctober 29, 1918. Serial'No. 260,171.

tioned. I mix with a metallic sulphate such a quantity of an alkalinesub-stance, which when in a dry statewill not react therewith, as will,together with the alkaline content of the water, insure a completeprecipita tion of the metallic portion of the metallic sulphate whenapplied to the water to, be

purified. My coagulant is preferably up plied to the water in powderedform. The ingredients may be powdered before mixing, or mixed and thenpowdered. I have manufactured an aluminum salt suitable for th1s purposeby crushing into fine particles 3.82 parts of nitre cake the principalin gredient of which is acid sodium sulphate, NaHSO and mixing the samewith one part of crushed bauxite, a mineral consist ing of approximatelyfifty per centum of alumina A1 0 and then heating until sulphate ofaluminum Al (SO is formed.

The resultant'product, is then reduced to a powder. It is apparent thata similar product maybe produced with other acid bearing salts and otheraluminum bearing minerals, such as clay.

I have obtained satisfactory results by mixing parts of this productwith from 5*to 2t) parts-of ground lime stone, the ratio of ground limestone depending upon the alkalinity of the water to be treated. Theseingredients I mix thoroughly in a dry state andffjthen add to the waterto be treated, as required.

\Vhile I prefer. to use-ground lime rock because it is readily availablein most sections at a moderate cost, I may use any commercial calciumcarbonate as for instance, precipitated calcium carbonate or calciumcarbonate mingled with magnesium carbonate or any other impurity whichisfrequently present in ground lime rock and which will notre'eact withthe metallic salt in a dry state.

After the coagulation the impurities may be removed by sedimentation orfiltration, or both. I 1

The coagulant and process of purifying water herein described isparticularly adapted for purifying water which contains a small amountof carbon dioxide or of calcium bicarbonate or of magnesium bicarbonate.The amounts of carbon dioxide or of such bicarboiuites in the waterstobe purified by this process may be very small in ltltl form calciumbicarbonate:

tion of the metallic sulphate.

uantity, the amount required being only t e small quantity necessary toinitiate the following chemical reaction.

Assuming that the mixture which I employ to produce the coagulationconsists of calcium carbonate, CaCO and aluminum sulphate Al (SO4) .18HO, the reactions will be as follows: i

1. A portion of the aluminum sulphate will react with the calciumbicarbonate in the water producing precipitated aluminum hydroxide: A1(SOQ .18H (){3Ga(HCO :Al,(OH) +3CaSO +6CO +18H Q 2. The carbon dioxide,CO will, in the presence of water and the calciumcarbonate, 3CaCO +6CO3H O:3Ca (H00 2.

The second reaction results in the formation of the same amount ofcalcium bicarbonate which was taken from the water. to produce thealuminum hydroxide precipitate formed in the first reaction andthiscalcium bicarbonate again institutes a reaction similar to the firstreaction, after which the 'second reaction takes place and the cycle iscontinuous until all of the aluminum sul-v carbonates 1n the mixture,together with the phate has reacted.

Having described my invention,I claim: 1. A dry coagulant for purifyingwater composed of a mixture of dry mono-carbonate of calcium and drymetallic sulphate adapted to be fed as a mixture'in thedry state to thewater.

' 2. A dry coagulant for purifying water composed of a mlxture ofmono-carbonate of calcium and metallic sulphate, the said materialsbelng mlxed and maintained in a dry condition preventing prematurereaction, and adapted to be fed in the dry state to the water to'bepurified.

3. A dry re-agent for purifying water comprising a' mixture ofcommercial mono-' carbonate of calcium and a metallic sulphate both in adry state and which willnot re-act together when in a, dry state.

4. A dry re-agent for purifying water comprising a mixture of commercialmonocarbonate of calcium and a metallic sulphate both in a dry state andwhich will not react together when in a dry state; the ratio of theingredients being such that the/quantity of-carbonate in the mixture issufiicient to completely re-act with the metallic por- 5. A dry re-agentforpurifying water comprising a mixture of commercial monocarbonate ofcalcium and a metallic sulphate both in a dry state and which 'will notre-act together when in a dry state; the ratio of the ingredients beingsuch that the quantity of carbonate in the mixture together with thealkalinityin the water to be purified is sufiicient to completely reactwith the metallic portion of the metallic sulphate.

6. A dry" reagent for purifying water comprising a mixture of commercialmonocarbonate of calcium and a metallic salt both in a dry state andwhich will not react together when in a dry state. 7. A dry reagent forpurifying water comprising a mixture of commercial monocarbonate ofcalcium'a'nd a metallic salt both in a dry state and which will notre-act together when in a dry state; the ratio of the ingredients beingsuch that the quantity of carbonate in the mixture is sufficient tocompletely rc-act with the metallic portion of the metallic salt, I

8. A dry re-agent for purifying water comprising a mixture of commercialmonocarbonate of calcium and a metallic salt both in a dry state andwhich will'not re-act together when, in a dry state; the ratio of theingredients being such that the quantity of alkalinity of the water tobe purified is fsufiicient to completely re-act with the metallicportion of the metallic salt.

.9. The process of purifying water which comprises mingling commercialmono-carbonate of-calcium with an acid metallic salt which will notre-act therewith when in a dry state and then feeding the dry mixture tothe water to be treated.

10. The process of purifying waterwhich comprises mingling commercialmono carbonate of calcium with an acid 'metallic 'salt which will notre-act therewith when ill] a dry state but will re-act in the presenceof water. 7

11. The process of purifying water which comprises mingling commercialmono-carbonate of calcium with an acid metallic salt which will notreact therewith when in a .dry state but willre-act in the presence ofwater, the quantity of carbonates in the mixture being sutlicient tocompletely re-act with New York, this 1

